Caption: Rectal prolapse surgery. Surgeon carrying out a Delorme's procedure to repair an 80 year old female's prolapsed rectum. Prolapse occurs when the muscles supporting the rectum are weakened causing the walls to collapse and protrude through the anus. During this procedure the prolapsed lining (mucosa) is removed and the underlying muscles folded and stitched together to strengthen the rectum. The procedure is carried out through the anus.